Mercurial > dropbear
diff svr-session.c @ 1653:76189c9ffea2
External Public-Key Authentication API (#72)
* Implemented dynamic loading of an external plug-in shared library to delegate public key authentication
* Moved conditional compilation of the plugin infrastructure into the configure.ac script to be able to add -ldl to dropbear build only when the flag is enabled
* Added tags file to the ignore list
* Updated API to have the constructor to return function pointers in the pliugin instance. Added support for passing user name to the checkpubkey function. Added options to the session returned by the plugin and have dropbear to parse and process them
* Added -rdynamic to the linker flags when EPKA is enabled
* Changed the API to pass a previously created session to the checkPubKey function (created during preauth)
* Added documentation to the API
* Added parameter addrstring to plugin creation function
* Modified the API to retrieve the auth options. Instead of having them as field of the EPKASession struct, they are stored internally (plugin-dependent) in the plugin/session and retrieved through a pointer to a function (in the session)
* Changed option string to be a simple char * instead of unsigned char *
| author | fabriziobertocci <fabriziobertocci@gmail.com> |
|---|---|
| date | Wed, 15 May 2019 09:43:57 -0400 |
| parents | 92c93b4a3646 |
| children | cc0fc5131c5c |
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--- a/svr-session.c Wed Mar 27 22:15:23 2019 +0800 +++ b/svr-session.c Wed May 15 09:43:57 2019 -0400 @@ -88,6 +88,18 @@ m_free(svr_ses.remotehost); m_free(svr_ses.childpids); svr_ses.childpidsize = 0; + +#if DROPBEAR_EPKA + if (svr_ses.epka_plugin_handle != NULL) { + if (svr_ses.epka_instance) { + svr_ses.epka_instance->delete_plugin(svr_ses.epka_instance); + svr_ses.epka_instance = NULL; + } + + dlclose(svr_ses.epka_plugin_handle); + svr_ses.epka_plugin_handle = NULL; + } +#endif } void svr_session(int sock, int childpipe) { @@ -101,10 +113,6 @@ #if DROPBEAR_VFORK svr_ses.server_pid = getpid(); #endif - svr_authinitialise(); - chaninitialise(svr_chantypes); - svr_chansessinitialise(); - svr_algos_initialise(); /* for logging the remote address */ get_socket_address(ses.sock_in, NULL, NULL, &host, &port, 0); @@ -114,6 +122,56 @@ m_free(host); m_free(port); +#if DROPBEAR_EPKA + /* Initializes the EPKA Plugin */ + svr_ses.epka_plugin_handle = NULL; + svr_ses.epka_instance = NULL; + if (svr_opts.pubkey_plugin) { +#if DEBUG_TRACE + const int verbose = debug_trace; +#else + const int verbose = 0; +#endif + PubkeyExtPlugin_newFn pluginConstructor; + + /* RTLD_NOW: fails if not all the symbols are resolved now. Better fail now than at run-time */ + svr_ses.epka_plugin_handle = dlopen(svr_opts.pubkey_plugin, RTLD_NOW); + if (svr_ses.epka_plugin_handle == NULL) { + dropbear_exit("failed to load external pubkey plugin '%s': %s", svr_opts.pubkey_plugin, dlerror()); + } + pluginConstructor = (PubkeyExtPlugin_newFn)dlsym(svr_ses.epka_plugin_handle, DROPBEAR_PUBKEY_PLUGIN_FNNAME_NEW); + if (!pluginConstructor) { + dropbear_exit("plugin constructor method not found in external pubkey plugin"); + } + + /* Create an instance of the plugin */ + svr_ses.epka_instance = pluginConstructor(verbose, svr_opts.pubkey_plugin_options, svr_ses.addrstring); + if (svr_ses.epka_instance == NULL) { + dropbear_exit("external plugin initialization failed"); + } + /* Check if the plugin is compatible */ + if ( (svr_ses.epka_instance->api_version[0] != DROPBEAR_EPKA_VERSION_MAJOR) || + (svr_ses.epka_instance->api_version[1] < DROPBEAR_EPKA_VERSION_MINOR) ) { + dropbear_exit("plugin version check failed: " + "Dropbear=%d.%d, plugin=%d.%d", + DROPBEAR_EPKA_VERSION_MAJOR, DROPBEAR_EPKA_VERSION_MINOR, + svr_ses.epka_instance->api_version[0], svr_ses.epka_instance->api_version[1]); + } + if (svr_ses.epka_instance->api_version[1] > DROPBEAR_EPKA_VERSION_MINOR) { + dropbear_log(LOG_WARNING, "plugin API newer than dropbear API: " + "Dropbear=%d.%d, plugin=%d.%d", + DROPBEAR_EPKA_VERSION_MAJOR, DROPBEAR_EPKA_VERSION_MINOR, + svr_ses.epka_instance->api_version[0], svr_ses.epka_instance->api_version[1]); + } + dropbear_log(LOG_INFO, "successfully loaded and initialized pubkey plugin '%s'", svr_opts.pubkey_plugin); + } +#endif + + svr_authinitialise(); + chaninitialise(svr_chantypes); + svr_chansessinitialise(); + svr_algos_initialise(); + get_socket_address(ses.sock_in, NULL, NULL, &svr_ses.remotehost, NULL, 1); @@ -151,6 +209,13 @@ char fullmsg[300]; int i; +#if DROPBEAR_EPKA + if ((ses.epka_session != NULL)) { + svr_ses.epka_instance->delete_session(ses.epka_session); + } + ses.epka_session = NULL; +#endif + /* Render the formatted exit message */ vsnprintf(exitmsg, sizeof(exitmsg), format, param);